[fix](crash) be crash on ~LRUFileCache (#42498)

come from: #39036

Crash stack:
```
(gdb) bt
#0  0x00007ff5c8c6c387 in raise () from /lib64/libc.so.6
#1  0x00007ff5c8c6da78 in abort () from /lib64/libc.so.6
#2  0x0000561eb0a5e38a in __gnu_cxx::__verbose_terminate_handler () at ../../../../libstdc++-v3/libsupc++/vterminate.cc:95
#3  0x0000561eb0a5caf6 in __cxxabiv1::__terminate (handler=<optimized out>) at ../../../../libstdc++-v3/libsupc++/eh_terminate.cc:48
#4  0x0000561eb0a5cb61 in std::terminate () at ../../../../libstdc++-v3/libsupc++/eh_terminate.cc:58
#5  0x0000561ea4028552 in doris::io::LRUFileCache::~LRUFileCache (this=0x7ff540fed000) at /root/be/src/io/cache/block/block_lru_file_cache.h:62
#6  0x0000561ea402857e in doris::io::LRUFileCache::~LRUFileCache (this=0x33688) at /root/be/src/io/cache/block/block_lru_file_cache.h:54
#7  0x0000561ea4251cd2 in std::default_delete<doris::io::IFileCache>::operator() (this=0x7ff54101d000, __ptr=0x33688)
    at /var/local/ldb-toolchain/bin/../lib/gcc/x86_64-linux-gnu/11/../../../../include/c++/11/bits/unique_ptr.h:85
#8  std::unique_ptr<doris::io::IFileCache, std::default_delete<doris::io::IFileCache> >::~unique_ptr (this=0x7ff54101d000)
    at /var/local/ldb-toolchain/bin/../lib/gcc/x86_64-linux-gnu/11/../../../../include/c++/11/bits/unique_ptr.h:361
#9  std::destroy_at<std::unique_ptr<doris::io::IFileCache, std::default_delete<doris::io::IFileCache> > > (__location=0x7ff54101d000)
    at /var/local/ldb-toolchain/bin/../lib/gcc/x86_64-linux-gnu/11/../../../../include/c++/11/bits/stl_construct.h:88
#10 std::_Destroy<std::unique_ptr<doris::io::IFileCache, std::default_delete<doris::io::IFileCache> > > (__pointer=0x7ff54101d000)
    at /var/local/ldb-toolchain/bin/../lib/gcc/x86_64-linux-gnu/11/../../../../include/c++/11/bits/stl_construct.h:138
#11 std::_Destroy_aux<false>::__destroy<std::unique_ptr<doris::io::IFileCache, std::default_delete<doris::io::IFileCache> >*> (__first=0x7ff54101d000, 
    __last=0x7ff54101d008) at /var/local/ldb-toolchain/bin/../lib/gcc/x86_64-linux-gnu/11/../../../../include/c++/11/bits/stl_construct.h:152
#12 std::_Destroy<std::unique_ptr<doris::io::IFileCache, std::default_delete<doris::io::IFileCache> >*> (__first=<optimized out>, __last=0x7ff54101d008)
    at /var/local/ldb-toolchain/bin/../lib/gcc/x86_64-linux-gnu/11/../../../../include/c++/11/bits/stl_construct.h:184
#13 std::_Destroy<std::unique_ptr<doris::io::IFileCache, std::default_delete<doris::io::IFileCache> >*, std::unique_ptr<doris::io::IFileCache, std::default_delete<doris::io::IFileCache> > > (__first=<optimized out>, __last=0x7ff54101d008)
    at /var/local/ldb-toolchain/bin/../lib/gcc/x86_64-linux-gnu/11/../../../../include/c++/11/bits/alloc_traits.h:746
#14 std::vector<std::unique_ptr<doris::io::IFileCache, std::default_delete<doris::io::IFileCache> >, std::allocator<std::unique_ptr<doris::io::IFileCache, std::default_delete<doris::io::IFileCache> > > >::~vector (this=0x7ff596a24ba8)
    at /var/local/ldb-toolchain/bin/../lib/gcc/x86_64-linux-gnu/11/../../../../include/c++/11/bits/stl_vector.h:680
#15 doris::io::FileCacheFactory::~FileCacheFactory (this=0x7ff596a24b80) at /root/be/src/io/cache/block/block_file_cache_factory.h:42
#16 doris::ExecEnv::destroy (this=0x561eb130b800 <doris::ExecEnv::GetInstance()::s_exec_env>) at /root/be/src/runtime/exec_env_init.cpp:651
#17 0x0000561ea35c3fe3 in main (argc=<optimized out>, argv=<optimized out>) at /root/be/src/service/doris_main.cpp:628
```

be/src/io/cache/block/block_lru_file_cache.h

@@ -54,7 +54,7 @@ class LRUFileCache final : public IFileCache {
     ~LRUFileCache() override {
         _close = true;
         if (_cache_background_load_thread.joinable()) {
-            _cache_background_thread.join();
+            _cache_background_load_thread.join();
         }
         if (_cache_background_thread.joinable()) {
             _cache_background_thread.join();